1. Field of the Invention
The present invention relates to an air conditioning system, and more particularly, to an air conditioning system, which can improve the performance and stability of the system by controlling such that the ratio of a liquid refrigerant in the refrigerant injected into a compressor may be less than a predetermined value.
2. Discussion of the Related Art
Generally, an air conditioning system is an apparatus which cools or heats indoor spaces by compressing, condensing, expanding, and evaporating a refrigerant.
The air conditioning systems are classified into a normal air conditioner including an outdoor unit and an indoor unit connected to the outdoor unit and a multi-type air conditioner including an outdoor unit and a plurality of indoor units connected to the outdoor unit. Moreover, the air conditioning systems are classified into a cooling air conditioner supplying a cool air only to an indoor space by driving a refrigerant cycle in one direction only and a cooling and heating air conditioner supplying a cool or hot air to an indoor space by driving a refrigerant cycle selectively and bi-directionally.
The air conditioning system includes a compressor, a condenser, an expansion valve, and an evaporator. The refrigerant discharged from the compressor is condensed in the condenser, and then expands in the expansion valve. The expanded refrigerant is evaporated in the evaporator, and then sucked into the compressor. IN a cooling operation or heating operation, a gaseous refrigerant is injected into the compressor, thus improving performance.
However, in a case where excessive liquid refrigerant exists in a refrigerant being injected, liquid compression may occur and this may lead to damage to the compressor.